Bioremediation reactor system and method

ABSTRACT

In some embodiments, a wastewater treatment system may reduce contaminants in water. A system may include one or more bioreactors which include a substrate that supports a biofilm. The bacteria used to form the biofilm may be selected to maximize the reduction of contaminants in water. Various components of the wastewater treatment system may be optimized to improve the efficiency and energy consumption of the wastewater system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/671,901, filed Nov. 8, 2012, now U.S. Pat. No. 8,920,651, which is acontinuation of U.S. patent application Ser. No. 13/480,019 filed May24, 2012, now abandoned, which claims priority to U.S. ProvisionalApplication No. 61/489,937 filed on May 25, 2011.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to systems and methods fortreating water. More particularly, the invention relates to thereduction of contaminants from wastewater using bacteria.

2. Description of the Relevant Art

Domestic wastewater contains various physical, chemical andbacteriological constituents, which require treatment prior to releaseto the environment. Various wastewater treatment processes exist whichprovide for the reduction of oxygen demanding materials, suspendedsolids and pathogenic organisms. Reduction of nutrients, principallyphosphorous and nitrogen, has been practiced primarily since the 1960'sat treatment plants where there is a specific need for nutrientreduction to protect the water quality and, hence, the uses of thereceiving waters, whether ground water or surface water. The primaryreasons for nutrient reduction are to protect water quality for drinkingwater purposes, as there is a drinking water standard for nitrite andnitrate, and to reduce the potential for eutrophication in nutrientsensitive surface waters by the reduction of nitrogen and/or phosphorus.

Fluidized bed bioreactors have been used to treat wastewater. In afluidized bed bioreactor, granular media containing bacteria may bepositioned in a water column and fluidization may be obtained by liquidrecirculation or by external gas fed into the bioreactor. During use abiomass forms on the granular media. Wastewater may be processed throughthe bioreactor by contacting the wastewater with the biomass.Alternatively, an activated sludge from operational wastewater treatmentsystems may be used to form a biofloc or biomass. The formation of abiofloc or biomass from the sludge may be time consuming and may notallow customization for specific wastewater contaminants. In addition,as bacteria in a biofloc or biomass fall off of the mass and/or die, asystem to replenish specific strains of bacteria in the biofloc may notexist.

Improvements to existing bioreactors are desirable to improve theefficiency and longevity of biological water treatment systems.

SUMMARY OF THE INVENTION

In an embodiment, a system for reducing contaminants in a wastewaterstream includes an inlet system, a sedimentation system and one or morebioreactors. The inlet system receives a wastewater stream including oneor more contaminants. The sedimentation system is coupled to the inletsystem. The sedimentation system includes a sedimentation system outletsystem. During use, the sedimentation system removes at least a portionof solid, inorganic materials in the wastewater stream to create an atleast partially clarified wastewater stream that is passed to thesedimentation system outlet system. One or more bioreactors are coupledto sedimentation system outlet system. One or more of the bioreactorsinclude one or more substrates and one or more bacteria capable ofreducing the concentration of contaminants in the wastewater stream,wherein one or more of the bacteria at least partially adhere to one ormore of the substrates. The at least partially clarified wastewaterstream passes from the sedimentation system into one or more of thebioreactors where at least a portion of the contaminants in the at leastpartially clarified wastewater stream are removed by bacteria in the oneor more bioreactors during use. The sedimentation system and one or moreof the bioreactors, in some embodiments, are housed together in aportable structure.

In one embodiment, the sedimentation system outlet system includes aweir system and an outlet conduit, wherein the wastewater in thesedimentation system enters the weir system and passes through the weirsystem to the outlet conduit. In an embodiment, the weir system includesa first wall and an opposing second wall, wherein the first wall andsecond wall together define a conduit through which wastewater passesthrough the weir system. The second wall, in some embodiments, includesa saw tooth upper surface, wherein the wastewater passes through theconduit defined by the first wall and the second wall, and over the sawtooth upper surface of the second wall, into the outlet conduit.

In some embodiments, one or more of the bioreactors include an oxygencontaining gas inlet wherein during operation of the bioreactor oxygencontaining gas passes through the oxygen containing gas inlet into thebioreactor. One or more of the bioreactors may also include a diffusercoupled to the oxygen containing gas inlet, wherein during operation ofthe bioreactor oxygen containing gas passes through the oxygencontaining gas inlet into the diffuser and through the diffuser into thebioreactor.

In some embodiments, the substrate disposed in a bioreactor include apolymer substrate. Other embodiments may include a ceramic substrate. Inone embodiment, one or more of the bacteria include primary adhererbacteria that couple to the substrate and wherein one or more bacteriainclude secondary bacteria which couple to the primary adherer bacteriato form a biofilm. In some embodiments, the secondary bacteria aresubstantially unable to couple to the substrate. Examples of bacteriathat may be present in a bioreactor include one or more of thefollowing: bacteria of the genus Caulobacter; bacteria of the genusEnterobacter; bacteria of the genus Pseudomonas; bacteria of the genusGordonia; bacteria of the genus Bacillus; bacteria of the genusAgrobacterium; and bacteria of the genus Zoogloea.

A bacteria inlet may be coupled to the sedimentation system outletsystem, wherein one or more of the bacteria capable of reducing theconcentration of contaminants in the wastewater stream are introducedinto the bioreactors through the bacteria inlet. The system may alsoinclude one or more bacteria generators configured to supply bacteria toone or more of the bioreactors. In some embodiments, a plurality ofbacteria generators configured to supply bacteria to one or more of thebioreactors, wherein each of the bacteria generators is independentlyoperable.

In some embodiments, a filtration system is coupled to one or morebioreactors, wherein the filtration system receives an effluent streamfrom one or more of the bioreactors and produces a filtered water streamfrom the effluent stream.

In some embodiments, a grinding system is coupled to the inlet systemand the sedimentation system, wherein the wastewater stream is passedthrough the grinding system and transferred to the sedimentation systemduring use, and wherein the grinding system reduces the size of solidmatter in a water stream passing through the grinding system.

One or more fluid level sensors may be disposed in one or more of thebioreactors. The fluid sensors may be coupled to a controller. Duringuse, the controller controls operation of a pump, coupled to thecontroller, to control the incoming flow of the at least partiallyclarified wastewater stream into the one or more bioreactors based, inpart, on the fluid level detected by one or more of the fluid levelsensors.

In an embodiment, a system for reducing contaminants in a wastewaterstream includes an inlet system and one or more bioreactors. The inletsystem receives a wastewater stream including one or more contaminants.One or more bioreactors are coupled to inlet system. One or more of thebioreactors include one or more substrates and one or more bacteriacapable of reducing the concentration of contaminants in the wastewaterstream, wherein one or more of the bacteria at least partially adhere toone or more of the substrates. A bioreactor inlet may be coupled to theinlet system, the bioreactor inlet being positioned below one or more ofthe substrates, wherein the wastewater stream enters the bioreactorthrough the bioreactor inlet during use. A bioreactor outlet system maybe positioned above one or more of the substrates, wherein thebioreactor outlet system includes a weir system and a bioreactor outletconduit, wherein water in the bioreactor enters the weir system andpasses through the weir system to the bioreactor outlet conduit. In anembodiment, the weir system includes a first wall and an opposing secondwall, wherein the first wall and second wall together define a conduitthrough which water passes through the weir system. A top surface of thefirst wall may be positioned above the top surface of the second wall,wherein water passes over the first wall and into the conduit defined bythe first wall and the second wall.

In an embodiment, a system for reducing contaminants in a wastewaterstream includes an inlet system and one or more bioreactors. The inletsystem receives a wastewater stream including one or more contaminants.One or more bioreactors are coupled to inlet system. One or more of thebioreactors include one or more substrates and one or more bacteriacapable of reducing the concentration of contaminants in the wastewaterstream, wherein one or more of the bacteria at least partially adhere toone or more of the substrates. In some embodiments, the substrateincludes a plurality of sheets, and wherein the sheets are oriented,with respect to each other, such that a plurality of passages aredefined by the sheets. In one embodiment, one or more of the sheets ofthe substrate include ridges and/or grooves, wherein the sheets arepositioned proximate to each other such that the ridges and/or groovesare at least partially aligned to define a plurality of passages. In anembodiment, the substrate includes a plurality of corrugated sheets,wherein the sheets are oriented, with respect to each other, such that aplurality of passages are defined by the corrugated sheets. In someembodiments, the substrate is a ceramic substrate. For example, asubstrate may include a plurality of porous ceramic rocks. The rocks maybe constrained to a mechanism to build a colony, with respect to eachother, such that a plurality of passages are defined by the rocks.

In an embodiment, a system for reducing contaminants in a wastewaterstream includes an inlet system, a buffer system and one or morebioreactors. The inlet system receives a wastewater stream including oneor more contaminants. The wastewater stream is stored in the buffersystem prior to transferring the wastewater stream into one or more ofthe bioreactors. One or more of the bioreactors include one or moresubstrates and one or more bacteria capable of reducing theconcentration of contaminants in the wastewater stream, wherein one ormore of the bacteria at least partially adhere to one or more of thesubstrates. In one embodiment, an oxygen containing gas inlet is coupledto the buffer system. During use, oxygen containing gas passes throughthe oxygen containing gas inlet into the buffer system such that theconcentration of oxygen in the wastewater stream is increased prior totransferring the wastewater stream into one or more of the bioreactors.In some embodiments, a grinding system is coupled to the inlet system,wherein the wastewater stream is passed through the grinding system andtransferred to the buffer system, wherein the grinding system reducesthe size of solid matter in a water stream passing through the grindingsystem. In some embodiments, the buffer system includes a surge tankcoupled to the inlet system and an equalization tank coupled to thesurge tank, wherein wastewater is stored in the surge tank and passed tothe equalization tank during use. A grinding system may be coupled tothe surge tank, wherein the wastewater stream is passed from the surgetank, through the grinding system, to the equalization tank, wherein thegrinding system reduces the size of solid matter in a water streampassing through the grinding system.

In an embodiment, a system for reducing contaminants in a wastewaterstream includes an inlet system, one or more bioreactors, and a metalremoving system. The inlet system receives a wastewater stream includingone or more contaminants. One or more bioreactors are coupled to inletsystem. One or more of the bioreactors include one or more substratesand one or more bacteria capable of reducing the concentration ofcontaminants in the wastewater stream, wherein one or more of thebacteria at least partially adhere to one or more of the substrates. Ametal removing system is coupled to one or more of the bioreactors,wherein the metal removing system removes at least a portion of metalions in the wastewater stream. In some embodiments, metal removingsystem includes at least two metal objects disposed at a fixed distancefrom each other, wherein, during use, an electrical potential is appliedto the metal objects to remove at least a portion of the metal ions fromthe wastewater stream. In some configurations, the metal removing systemcauses at least a portion of the metal ions in the water stream toprecipitate out of the wastewater stream when an electrical potential isapplied to the metal objects. In other configurations, the metalremoving system causes at least a portion of the metal ions to becomeplated onto one or more of the metal objects when an electricalpotential is applied to the metal objects.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the present invention will become apparent to thoseskilled in the art with the benefit of the following detaileddescription of embodiments and upon reference to the accompanyingdrawings in which:

FIG. 1 depicts a schematic diagram of a wastewater treatment system;

FIG. 2 depicts a projection view of a buffer system of a wastewatertreatment system;

FIG. 3 depicts a partially open projection view of a sedimentationsystem of a wastewater treatment system;

FIG. 4 depicts a partially open projection view of an embodiment of abioreactor of a wastewater treatment system;

FIG. 5 depicts a projection view of an embodiment of a substrate thatincludes a plurality of corrugated sheets;

FIG. 6 depicts a partially open projection view of a portable structurethat includes a pair of bioreactors and a sedimentation system;

FIG. 7 depicts a projection view of a control compartment;

FIG. 8 depicts a schematic diagram of a bacteria generation system;

FIG. 9 depicts a cross-sectional view of a control unit;

FIG. 10 depicts a schematic diagram of a non-buffered wastewatertreatment system; and

FIG. 11 depicts a schematic diagram of a buffered wastewater treatmentsystem.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. Thedrawings may not be to scale. It should be understood, however, that thedrawings and detailed description thereto are not intended to limit theinvention to the particular form disclosed, but to the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the present invention as definedby the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It is to be understood the present invention is not limited toparticular devices or methods, which may, of course, vary. It is also tobe understood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting. As used in this specification and the appended claims, thesingular forms “a”, “an”, and “the” include singular and pluralreferents unless the content clearly dictates otherwise. Furthermore,the word “may” is used throughout this application in a permissive sense(i.e., having the potential to, being able to), not in a mandatory sense(i.e., must). The term “include,” and derivations thereof, mean“including, but not limited to.” The term “coupled” means directly orindirectly connected.

An “air source” refers to a device capable of providing air or othergasses to a liquid.

“Bacteria” refers to any member of the Bacteria Domain.

A “bacteria generator” refers to a device capable of allowing one ormore bacteria to grow and/or reproduce.

A “biofilm” refers to a collection of more than one bacteria coupledtogether.

A “contaminant” refers to any unwanted substance or compound.

“Coupling” refers to attaching, bonding, adhering, welding, or a directconnection of two or more objects.

“Enteric bacteria” refers to bacteria that are found in the digestivetract of animals.

A “filament” refers to a portion of a bacterium that extends from thebody of the bacterium.

“Foam” refers to an aggregate of gas bubbles formed in a liquid orsolid. Foam in a liquid may suspend solid particles and inhibit settlingof the solid particles to a bottom of a container.

A “footprint” refers to an area on a surface an object occupies.

“Gene-up regulation” refers to activation of a property of a bacteriumafter the bacterium couples to a substrate. For example, a gene may beactivated, protein synthesis may occur, and/or metabolic activity may beincreased or decreased during gene-up regulation of a bacterium.

A “heterotroph” is an organism that requires organic compounds as acarbon source for growth and development. A heterotroph is not able touse carbon dioxide as its sole carbon source.

A “hydrophobic substrate” refers to a substrate that does not formhydrogen bonds with itself, which causes it to at least partially repelwater.

An “oligotroph” refers to an organism that can live in environments witha carbon concentration of less than 1 ppm.

An “organic compound” refers to a compound that includes carbon. Anorganic compound may include elements other than carbon, such as oxygen,nitrogen, sulfur, and/or metals.

“Primary adherer bacteria” refers to any member of the Bacteria Domaincapable of coupling to a substrate and/or other bacteria.

“Stagnant regions” refers to areas that are not substantially flowing.

“Secondary adherer bacteria” refers to any member of the Bacteria Domaincapable of coupling to other bacteria with a greater binding affinitythan the binding affinity of the bacteria for a substrate.

“Reducing contaminants in water” refers to reducing an amount ofcontaminant in water, degrading contaminants, altering contaminants(e.g., altering a metal contaminant such that it precipitates),absorbing contaminants, immobilizing contaminants, and/or removing oneor more contaminants from water.

“Wastewater” refers to a fluid comprising one or more contaminants.Contaminants include organic compounds, bacteria, and metal ions.Wastewater may also include solid inert materials such as undissolvedpolymeric materials, dirt, and sand.

In one embodiment, a waste treatment system includes one or morebioreactors. The wastewater treatment system further includes additionalcomponents that may assist in the transport of wastewater to thebioreactors. For example, a wastewater treatment system may include agenerator, a filtration system, a control system, a power distributionsystem, a bacteria on-site fermenter, a primary settling tank, pumps,blower(s), air diffusers, one or more biofilm substrates, and sensors.

FIG. 1 depicts a schematic diagram of a wastewater treatment system 100.Wastewater treatment system 100 includes one or more bioreactors 200.One or more of bioreactors 200 include one or more substrates. In anembodiment, one or more bacteria disposed in bioreactor 200 at leastpartially adhere to one or more of substrates. During treatment of awastewater stream, wastewater is introduced into one or more ofbioreactors 200 and contacted with a biofilm formed on one or moresubstrates disposed within bioreactors 200. Interaction of thewastewater stream with bacteria present in bioreactor (e.g., bacteriacoupled to a substrate) allows the bacteria to reduce contaminants inthe wastewater stream.

Wastewater system 100 may be configured in different wastewater inputconfigurations. For example, wastewater system may be configured forbuffered or non-buffered wastewater input streams. For installationsthat include a customer supplied wastewater reservoir, a non-bufferedinput configuration may be used. In a non-buffered transfer system 300,wastewater stream is conducted to an influent filter 310. Influentfilter 310 may be an influent screen which separates some of the solidmatter from the wastewater stream. After passing through influent filter310 the wastewater stream may be conducted to a grinding system 320.Grinding system 320 receives a wastewater stream that includes solidmatter and reduces the size of the solid matter in the wastewaterstream. Examples of a grinding system include, but are not limited to,grinders and macerating pumps. The resulting pretreated wastewaterstream is passed, in some embodiments, to a sedimentation system 500,using a pump. In some embodiments, grinding system 320 includes a pumpfor transferring the wastewater through the grinding system and tosedimentation system 500 (e.g., using a macerating pump).

For those installations that lack sufficient infrastructure to provide aconstant supply of wastewater for processing, a wastewater treatmentsystem may include a buffer unit 400 that accepts wastewater from anumber of sources with varying flow rates. In an embodiment, a bufferunit 400 includes an inlet system 410 that includes an influent pump 412and an inlet bypass valve 414. Influent pump 412 may be used to pump aninfluent wastewater stream into a surge tank 420. For example,wastewater may be pumped into surge tank 420 from a holding basin/liftstation. In some embodiments, an influent pump may not be required. Insuch embodiments, an influent bypass valve 414 may allow a wastewaterstream to bypass influent pump 412. Bypass valve may be an electricallyactuated valve. An influent pump may not be necessary if the wastewaterstream is pressurized when it is conducted to the wastewater treatmentsystem. For example, a holding tank (e.g., of a truck) may include apump for sending wastewater out of the holding tank. Surge tank 420collects wastewater and has a sufficient capacity to be able to providea substantially constant supply of wastewater into the wastewatertreatment system based on the frequency of wastewater delivery to thesystem.

Wastewater stored in surge tank 420 may be conducted to a grindingsystem 430. In some embodiments a buffer pump 435 may be coupled togrinding system to conduct the wastewater stream into an equalizationtank 440. Equalization tank 440 may include one or more gas diffusers442 coupled to blower 444. In some embodiments, oxygen may be added towastewater held in equalization tank by sending air (e.g., using blowers444) or oxygen (e.g., from a compressed oxygen source) into theequalization tank. Gas diffusers 442 may be coupled to the incomingoxygen source to disperse the incoming oxygen throughout the wastewaterin equalization tank 440. Water may be transferred from equalizationtank 440 to a sedimentation system 500, using transfer pump 450.Transfer pump 450 moves wastewater from equalization tank 440 tosedimentation system 500 at a controlled rate.

Sedimentation system 500 receives a waste stream from a buffer system400 or from a non-buffered transfer system 300. Sedimentation system 500removes at least a portion of solid material in the wastewater conductedto the sedimentation system to provide an at least partially clarifiedwastewater stream to the one or more bioreactors 200. The flow ofwastewater through sedimentation system 500 is controlled, in part byeither a pump in grinding system 300 (for non-buffered systems) or bytransfer pump 450 (in buffered systems).

Bioreactors 200 may receive an at least partially clarified wastewaterstream from sedimentation system 500. Bioreactors 200 include one ormore substrates and one or more bacteria that at least partially adhereto the substrate. In some embodiments, oxygen may be added to thebioreactors by sending air (e.g., using blowers 212) or oxygen (e.g.,from a compressed oxygen source) into the bioreactors. Gas diffusers 210may be coupled to the incoming oxygen source to disperse the incomingoxygen throughout the wastewater in bioreactors 200.

Water may be transferred from bioreactors 200 to a purification system600, using effluent transfer pump 610. Transfer pump 610 moveswastewater from bioreactors 200 to purification system 600 at acontrolled rate. In one embodiment, purification system 600 may includea filtration system that receives an effluent stream from one or more ofthe bioreactors and produces a filtered water stream. In an embodiment,purification system 600 includes a metal removing system (e.g., anelectrocoagulation system) that receives an effluent stream from one ormore bioreactors and reduces the concentration of metal ions in theeffluent stream. In some embodiments, refining system may include afiltration system and a metal removing system.

FIG. 2 depicts an embodiment of a buffer system 400. Buffer system 400includes a surge tank 420 and an equalization tank 440. In someembodiments, buffer system 400 may be stored in a portable structure460. For example, buffer system 400 may be stored in a high cube, 20′ISO container. As shown in FIG. 2, the components of buffer system 400may be stored in a single portable structure. In some embodiments,portable structure 460 includes integral roof ports 462 and a side door464 that allow for accessibility to the tanks and equipment within thestructure.

Surge tank 420 may, in some embodiments, be a cone-bottom tank. Surgetank 420 is supported by a complementary frame 422 which allows accessto the bottom. Use of a cone bottom tank will allow a preliminaryseparation of solids from the waste water stream. As wastewater enterssurge tank 420, solids will collect in the bottom of the tank. Bottomaccess of surge tank 420 provides an access point for the removal ofsolid materials that collect on the bottom of the tank. Surge tank 420is coupled to a wastewater inlet system 410 (depicted schematically inFIG. 1).

Buffer system 400 also includes an equalization tank 440. Equalizationtank 440 may include an oxygen containing gas inlet. In someembodiments, oxygen may be added to wastewater held in equalization tankby sending air (e.g., using blowers 444) or oxygen (e.g., from acompressed oxygen source) into equalization tank 440 through oxygencontaining gas inlet. Gas diffusers 442 may be coupled to the incomingoxygen containing gas inlet to disperse the incoming oxygen containinggas throughout the wastewater in equalization tank 440.

Together surge tank 420 and equalization tank 440 may provide storage ofa sufficient amount of wastewater to allow substantially continuousoperation of the wastewater treatment system. In some embodiments,buffer system 400 has a capacity of between about 3000 gallons to about6000 gallons; or between about 3500 gallons to about 5000 gallon. Insome embodiments, surge tank 420 has a lower capacity than equalizationtank 440. In some embodiments, surge tank 420 has a capacity of betweenabout 1000 gallons to about 2500 gallons, while equalization tank 440has a capacity of between about 2000 gallons and about 3500 gallons.

Surge tank 420 may be coupled to equalization tank 440 through agrinding system 430 and an buffer pump 435. During use wastewater,collected in surge tank 420, may be passed into grinding system 430.Grinding system 430 receives a wastewater stream that includes solidmatter and reduces the size of the solid matter in the wastewaterstream. In an embodiment, grinding system 430 includes an in-linegrinder. Buffer pump 435 is coupled to grinding system 430 to conductwastewater from surge tank 440 through the grinding system toequalization tank.

Integral sensors for flow control and biological condition feedback maybe mounted to surge tank 420 and/or equalization tank 440. Specifically,the tanks may incorporate one or more sensors, including, but notlimited to fluid level sensors, dissolved oxygen sensors, andPH/oxidation reduction potential sensors, as depicted in FIG. 1.Electrical power and signal wires are distributed in the buffer unitcontainer coupling the included sensors to a controller.

Buffer system 400 offers advantages over non-buffered wastewaterdelivery, even when a constant supply of wastewater is available. Whennon-buffered wastewater is delivered, the wastewater typically will havea higher solid level and a lower intrinsic oxygen level than wastewaterdelivered from a buffer system. The pretreated wastewater, obtained froma buffer system, will allow the bioreactors to operate more efficientlyand for longer periods of time, due to the reduced amount of solids andthe increased oxygen content.

A wastewater stream from a non-buffered source, or a pretreatedwastewater stream from a buffer system, may be conducted into asedimentation system 500. FIG. 3 depicts a partially open projectionview of a sedimentation system 500. Sedimentation system 500 includes aninlet hose 510 coupled to an inlet conduit 520. Wastewater is introducedinto sedimentation system through inlet hose 510 and into inlet conduit520. Inlet conduit 520 includes an opening 522 through which thewastewater enters the sedimentation system body 502. Opening 522 ispreferably positioned proximate to the lower half of the sedimentationsystem to ensure that the incoming wastewater is directed toward thebottom of body 502. The bottom of sedimentation system 500 includes asloped floor 504. During use, solid material, that is carried intosedimentation system 500 in the wastewater, settles on sloped floor 504,which directs the solid material toward solids outlet 506. Sloped floor504 helps to ensure that any solid material that settles out of thewastewater is directed toward the solids outlet 506. Sloped floor mayhave an approximately 10% to approximately 35% grade from horizontal. Inan embodiment, sloped floor may have approximately 23% to approximately27% grade from horizontal. Sedimentation system 200, in someembodiments, has a fluid capacity of between about 1000 gallons to about2500 gallons.

Sedimentation system body includes an outlet system 530. Outlet system530 includes a weir system 532 and an outlet conduit 534. Weir system532 is configured to inhibit the passage of at least a portion of thesolid matter in the wastewater from passing into the outlet conduit 534.Weir system 532 includes a first wall 533 and an opposing second wall535. Together first wall 533 and second wall 535 define a conduitthrough which the wastewater introduced into body 502 passes. As shownin FIG. 3, first wall 533 and second wall 535 may extend only part waydown the length of the body. This ensures that only wastewater that isnear the top of body 502 enters the weir system. Thus, incomingwastewater is directed toward the bottom of body 502, forcing wastewaterthat has already been introduced to move toward the top of body 502 andweir system 532. The relatively narrow opening formed between first wall533 and the second wall 535 ensures that a limited amount of wastewaterenters weir system 532 during use. Wastewater entering weir system 532,passes through the conduit defined by first wall 533 and second wall 535and over the second wall into outlet conduit 534. In some embodiments,first wall 533 extends to the roof of the body so that wastewaterentering weir system 532 is inhibited from leaving the weir system. Inone embodiment, second wall 535 includes a saw tooth upper surface, asdepicted in FIG. 3. During use, wastewater passes through the conduitdefined by first wall 533 and second wall 535 and over the saw toothupper surface of the second wall into outlet conduit 534. A saw toothupper surface on second wall 535 helps to improve sediment removal fromthe wastewater.

Sedimentation system also includes a fluid level sensor 540 to monitorthe level of wastewater in the sedimentation system. Fluid level sensor540 is coupled to a controller which is coupled to the transfer pump450. Controller, in some embodiments, will control the flow rate oftransfer pump 450, at least in part based on the fluid level insedimentation system 500.

The at least partially clarified waster from produced from thesedimentation system is transferred to one or more bioreactors 200. FIG.4 depicts a partially open projection view of an embodiment of abioreactor 200. Bioreactor 200 includes one or more substrates 250disposed in bioreactor 200. In an embodiment, one or more bacteriadisposed in bioreactor 200 at least partially adhere to one or more ofsubstrates. During treatment of a wastewater stream, wastewater isintroduced into one or more of bioreactors 200 from sedimentation system500 and contacted with a biofilm formed on one or more substrates 250disposed within bioreactors 200. Interaction of the wastewater streamwith bacteria present in bioreactor 200 (e.g., bacteria coupled to asubstrate) allows the bacteria to reduce contaminants in the wastewaterstream. Wastewater enters bioreactor 200 through an inlet hose 210having an outlet positioned proximate to the bottom of the bioreactorbody 202. In some embodiments, the outlet of inlet hose 210 ispositioned below one or more substrates 250 to ensure that the incomingwastewater contacts one or more substrates. In some embodiments,bioreactor 200 has a fluid capacity of about 1500 gallons to about 5000gallons.

Bioreactor 200 includes an outlet system 230. Outlet system 230 includesa weir system 232 and an outlet conduit 234. Weir system 232 isconfigured to inhibit the passage of at least a portion of the solidmatter in the bioreactor from passing into the outlet conduit 234. Weirsystem 232 includes a first wall 233 and an opposing second wall 235.Together first wall 233 and second wall 235 define a weir conduit 237through which the wastewater introduced into bioreactor 200 passes. Therelatively narrow area defined by first wall 233 ensures that a limitedamount of wastewater enters weir system 232 during use. A portion of thewastewater entering weir system 232, passes over first wall 233 andthrough the weir conduit 237 into outlet conduit 234. Only a portion ofthe wastewater that passes over the first wall enters weir conduit 237,the remainder of the wastewater passes through the weir system back intothe reactor. In this manner, the reduction of contaminants in awastewater stream can be maximized while maintaining a continuous flow.

In an embodiment, bioreactor 200 includes an oxygen containing gas inlet260 which receives an oxygen containing gas. An oxygen containing gasmay be air or oxygen obtained from a compressed gas source. An oxygencontaining gas enters bioreactor 200 through oxygen containing gas inlet260 and is conducted to one or more diffusers 210. The diffusersdisperse the incoming oxygen containing gas throughout the bioreactor.In some embodiments, diffusers create bubbles of oxygen containing gaswhich are dispersed within bioreactor 200.

Bioreactor 200 includes one or more substrates. A substrate may be astructure on which a biofilm grows in a container. One or moresubstrates are fixed within a bioreactor 200. In some instances, one ormore substrates are removably coupled to the bioreactor body to alloweasy removal for cleaning or replacement of the substrate. A substratemay be formed of polymeric material, including, but not limited to,polyvinyl chloride (PVC), polyethylene, and polypropylene. Othermaterials such as metals and natural materials (e.g., cotton) may beused to form one or more of the substrates. In certain embodiments, thematerial selected to form the substrate may not substantially degrade inthe presence of the wastewater to be treated.

A substrate may be planar, substantially cylindrical, substantiallyconical, substantially spherical, substantially rectangular,substantially square, substantially oval shaped, and/or irregularlyshaped. In some embodiments, a substrate includes a plurality of sheets.For example, as depicted in FIG. 4, substrate 250 includes a pluralityof sheets 252 oriented, with respect to each other, such that aplurality of passages are defined by the sheets. In some embodiments,sheets 252 include a plurality of ridges and/or grooves. The sheets maybe positioned proximate to each other such that the ridges and/orgrooves are at least partially aligned to define a plurality ofpassages. FIG. 5 depict a projection view of an embodiment of asubstrate that includes a plurality of corrugated sheets 256. In thisembodiment, corrugated sheets 256 are at least partially aligned todefine a plurality of passages 254 through the substrate. When disposedin a bioreactor, substrate 250, as depicted in FIG. 5, is oriented inthe direction of flow arrow 258 to maximize the surface area in contactwith the wastewater as it flows from the bottom of a bioreactor to thetop of the bioreactor.

Bioreactor 200 includes a fluid level sensor 270 to monitor the level ofwastewater in the bioreactor system. Fluid level sensor 270 is coupledto a controller which is coupled to the effluent transfer pump 610.Controller, in some embodiments, will control the flow rate of effluenttransfer pump 610, at least in part based on the fluid level inbioreactor 200.

In some embodiments, one or more bioreactors and one or moresedimentation systems may be stored in a portable structure. Forexample, one or more bioreactors and one or more sedimentation systemsmay be stored in a high cube, 20′ ISO container. FIG. 6 depicts aportable structure that includes two bioreactors 200 and a sedimentationsystem 500. Sedimentation system 500 is coupled to the two bioreactors200 through various plumbing connections disposed in control compartment700. In some embodiments, portable structure 290 includes integral roofports and one or more side doors that allow for accessibility to thetanks and equipment within the structure.

FIG. 7 depicts a projection view of control compartment 700. Componentsof control compartment 700 couple the two bioreactors 200 tosedimentation system 500. A wastewater inlet conduit 710 is disposed incontrol compartment 700. Wastewater inlet conduit 710 receiveswastewater from a non-buffered wastewater source or from buffer system400. Wastewater inlet conduit 710 is coupled to sedimentation system 500such that the incoming wastewater is transferred directly intosedimentation system 500.

After being processed in sedimentation system 500, wastewater istransferred to sedimentation system outlet conduit 720. Sedimentationsystem outlet conduit 720 is coupled to connector 722 which directs flowof wastewater from sedimentation system 500 into the bioreactors 200through bioreactor inlet conduits 724.

After wastewater is processed in bioreactors 200, an effluent streamfrom each bioreactor exits the bioreactors through bioreactor outletconduits 730. Treated wastewater passes from bioreactors 200 to effluenttransfer pump 610 which sends the treated wastewater out of thetreatment system through effluent transfer conduit 612. Treatedwastewater, in some embodiments, may be transferred to a purificationsystem 600, as depicted in FIG. 1.

Bioreactors 200 and sedimentation system 500 need to be periodicallydrained of solid materials that settle during use. Bioreactor drainconduits 760 are coupled to the bottom of bioreactors 200 and allowsolids and/or wastewater to be drained from the bioreactors.Sedimentation system drain conduit 765 is coupled to sedimentationsystem solids outlet 506. Sedimentation system drain conduit 765 allowssolids and/or wastewater to be drained from the sedimentation system.

Control compartment 700 may also include additional components used tooperate the sedimentation system and/or the bioreactors. For example,control compartment 700 may include a bacteria inlet conduit 740. Duringuse, bacteria, produced in a bacteria generator, may be transferred intothe treatment system (e.g., into the sedimentation system) throughbacteria inlet conduit 740. In an embodiment, bacteria inlet conduit 740is coupled to outlet conduit 534 of the sedimentation system. In thisconfiguration, bacteria is added to the at least partially clarifiedwastewater stream produced in the sedimentation system and flows withthe stream into the bioreactors. At least a portion of the bacteriaadded to the treatment system interacts with the substrate and/orbacteria coupled to the substrate to regenerate the biofilm.

Control compartment also includes effluent transfer pump 610, blowers212 and electronic controllers 750. Blowers 212 provide compressed airto bioreactors 200 through conduits 745. Conduits 745 may be coupled tovalves 747 which control the flow of compressed air from blowers 212into bioreactors 200. In an embodiment, conduits 745 are configured toallow compressed air to b passed from either blower to eitherbioreactor, individually or simultaneously. Electronic monitoringdevices such as DO sensor flow sensors, etc. that are disposed in eitherbioreactors 200 or sedimentation system 500 are coupled to electroniccontrollers 750. Electronic controllers may receive data from the sensorand communicate the information to a central controller.

The overall objectives of biological treatment of wastewater streams areto (1) transform (i.e., oxidize) dissolved and particulate biodegradableconstituents into acceptable end products, (2) capture and incorporatesuspended and non settleable colloidal solids into a biofilm, (3)transform or remove nutrients, such as nitrogen and phosphorus, and (4)in some cases, remove specific trace organic constituents and compounds.

In one embodiment, a wastewater treatment system utilizesphysiologically active microorganisms that are in logarithmic growthstage and are capable of participating in a biofilm on a hydrophobicsubstratum. In an embodiment, a microbial consortium is utilized in abioreactor for the treatment of wastewater. The microbial consortiumutilized in embodiments of a wastewater system is designed such thatspecific bacterial strains contribute to different aspects of healthybiofilm formation. For example, certain bacteria may be selected fortheir ability to perform adhesion to a substrate, while others wereselected on their ability to assist in intercellular adhesion.

The removal of dissolved and particulate carbonaceous material and thestabilization of organic matter found in wastewater is accomplishedbiologically using a variety of microorganisms, principally bacteria.Microorganisms are used to convert (e.g., oxidize) the dissolved andparticulate carbonaceous organic matter into simple end products andadditional biomass. Microorganisms may also be used to remove nitrogenand phosphorus in wastewater treatment processes. Specific bacteria arecapable of oxidizing ammonia (nitrification) to nitrite and nitrate,while other bacteria can reduce the oxidized nitrogen to gaseousnitrogen. The organic material and nutrients are removed from thewastewater flowing past the biofilm Aerobic heterotrophic bacteria areable to produce extracellular biopolymers that result in the formationof biofilms that can be separated from the treated liquid by gravitysettling with relatively low concentrations of free bacteria andsuspended solids. Because the biomass has a specific gravity slightlygreater than that of water, the biomass can be removed from the treatedliquid by gravity settling. It is important to note that unless thebiomass produced from the organic matter is removed on a periodic basis,complete treatment has not been accomplished because the biomass, whichitself is organic, will be measured as the BOD5 of the effluent. Withoutthe removal of biomass from the treated liquid, the only treatmentachieved is that associated with the bacterial oxidation of a portion ofthe organic matter originally present.

The efficient lowering of the BOD5 of the wastewater stream isaccomplished through the utilization of aerobic bacteria. The processrequires sufficient contact time between the wastewater andheterotrophic microorganisms, and sufficient oxygen and nutrients.During the initial biological uptake of the organic material, more thanhalf of it is oxidized and the remainder is assimilated as new biomass,which may be further oxidized by endogenous respiration. The smallamounts of remaining solids are periodically removed. The solids areseparated from the treated effluent by gravity separation as describedabove.

A wide variety of non-bacterial microorganisms are found in aerobicattached growth treatment process used for the removal of organicmaterial. Protozoa also play an important role in aerobic biologicaltreatment processes. By consuming free bacteria and colloidalparticulates, protozoa aid effluent clarification. Protozoa require alonger solids retention time than aerobic heterotrophic bacteria, preferdissolved oxygen concentrations above 1.0 mg/L, and are sensitive totoxic materials. Thus, their presence is a good indicator of atrouble-free stable process operation. Because of their size, protozoacan easily be observed with a light microscope at 100 to 200magnification. Rotifers can also be found in biofilms, as well asnematodes and other multicellular microorganisms. These organisms occurat longer biomass retention times, and their importance has not beenwell defined. Aerobic attached growth processes have a complex microbialecology.

In some embodiments, one or more bacteria may couple to a substrate in acontainer to form a biofilm. In an embodiment, bacteria forming thebiofilm may not substantially slough off of the substrate, during use.The bacteria may be aerobic. Some of the bacteria may be oligotrophic,heterotrophic, enteric, and/or combinations thereof.

The bacteria may be capable of reducing contaminants in wastewater. Insome embodiments, a biofilm may be capable of significantly reducingcontaminants in water quickly. For example, wastewater may only have toreside in a container with the biofilm for less than 24 hours tosignificantly reduce an amount of contaminants in the wastewater.

One or more of the bacteria may reduce an amount of and/or degradepesticides, industrial wastewater, wastewater from septic systems,and/or municipal wastewater. In some embodiments, one or more of thebacteria may reduce an amount of and/or degrade metal compounds and/ororganic compounds such as alkanes, alkenes, aromatic organic compounds,and/or polychlorinated benzenes. Some bacteria may cleave long chainbiopolymers into monomers, which other bacteria degrade. In anembodiment, bacteria may degrade at least a portion of organic compoundsinto at least carbon dioxide and water.

In some embodiments, a biofilm may include one or more primary adhererbacteria and/or one or more secondary adherer bacteria. Primary adhererbacteria may be capable of coupling to one or more substrates in acontainer and/or other bacteria. In certain embodiments, primary adhererbacteria may couple with a substrate such that the primary adhererbacteria are inhibited from being dislodged from the substrate duringuse. In an embodiment, primary adherer bacteria may irreversibly coupleto a substrate.

Primary adherer bacteria may have longitudinal and latitudinal sides. Insome bacteria, a longitudinal side may be longer than a latitudinal sideor vice versa. Primary adherer bacteria may couple to bacteria and/or asubstrate along a longitudinal and/or a latitudinal side. In anembodiment, a type of primary adherer bacteria may only couple to asubstrate on one of its latitudinal sides. Another type of primaryadherer bacteria may only couple to a substrate on one of itslongitudinal sides. A shape and/or a density of a biofilm may becontrolled by selecting one or more types of primary adherer bacteriathat have a preference for coupling with substrate along a specificside.

In some embodiments, primary adherer bacteria may include a stalk. Forexample, bacteria in the genus Caulobacter have a stalk. A stalk may bea narrower than the body of the primary adherer bacteria. A stalk may becapable of coupling to inanimate objects. An end of a stalk of a primaryadherer bacteria maybe couple to an inanimate object, such as asubstrate, but not couple to bacteria. For example, an end of a stalk ofa primary adherer bacteria may include a holdfast, such as a sugar basedholdfast, which allows the end of the stalk to bind with a substrate.

In an embodiment, a stalk may grow. A stalk of a primary adhererbacteria may be capable of growing from about 5 nm to about 200 nm. Itmay be advantageous to utilize a bacteria capable of extending abiofilm. If a food source is not plentiful proximate primary adhererbacteria with stalks, the stalks may grow to position the primaryadherer bacteria in another region of the fluid with a greater foodsource.

Primary adherer bacteria may include one or more filaments, such asorganelle, capable of coupling with other bacteria. For example,bacteria in the genus Gordonia have several filaments. Some primaryadherer bacteria may have filaments capable of coupling only with othertypes of bacteria (e.g., the filaments will not couple with the sameprimary adherer bacteria from the same genus).

In some embodiments, primary adherer bacteria may include bacteria fromthe class Actinobacteria Alphaproteobacteria, or combinations thereof.Primary adherer bacteria may include bacteria from the genus Gordonia,Caulobacter, or combinations thereof.

Secondary adherer bacteria may be capable of coupling with one or moreother bacteria including primary adherer bacteria. In some embodiments,secondary adherer bacteria may not be capable of coupling to asubstrate. In an embodiment, secondary adherer bacteria may includebacteria from the class Bacilli, Gammaproteobacteria,Betaproteobacteria, or combinations thereof. Secondary adherer bacteriamay include bacteria from the genus Bacillus, Pseudomonas, Zoogloea,Enterobacter, or combinations thereof.

Primary adherer bacteria and/or secondary adherer bacteria may becapable of reducing contaminants in water. Secondary adherer bacteriamay be capable of reducing a greater amount of one or more types ofcontaminants than one or more of the primary adherer bacteria. In someembodiments, sessile bacteria may experience gene-up regulation thatincreases the metabolic activity of the sessile bacteria. Sessilebacteria may have a metabolic activity four times the metabolic activityof planktonic bacteria. Primary adherer bacteria may experience gene-upregulation of metabolic activity due to their attachment to a substrateand/or secondary adherer bacteria may experience gene-up regulation dueto their attachment to other bacteria. In an embodiment, sessile primaryadherer bacteria may experience greater gene-up regulation of metabolicactivity that sessile secondary adherer bacteria.

In some embodiments, bacteria provided to a container may be selected toreduce specific contaminants. Bacteria may be selected for their abilityto withstand a pre-determined amount of a contaminant, such as 100 ppmof aromatic organic compound, and/or fluctuations in pH. For example,bacteria selected may include bacteria from the genus Enterobacter,Pseudomonas, Gordonia, Bacillus, Agrobacterium, Caulobacter, and/orZoogloea. The biofilm may include bacteria in the genus Nocardia,Thiothrix or Beggiatoa. In an embodiment, a biofilm may includeEnterobacter cloacae, Pseudomonas putida, Pseudomonas stutzeri, Gordoniasp., Bacillus subtilis, Agrobacterium sp., Caulobacter vibrioides,Caulobacter crescentus, and/or bacteria in the genus Zoogloea. Inanother embodiment, a biofilm may be formed from a combination ofbacteria, such as FreeFlow®, commercially available from NCH Corp(Irving, Tex.).

In some embodiments, the biofilm may include bacteria of the phylumActinobacteria phy. nov., class Actinobacteria, subclassActinobacteridae, order Actinomycetales, suborder Corynebacterineae,family Gordoniaceae, and/or genus Gordonia. In some embodiments,bacteria in the genus Gordonia may have filaments. The filaments may becapable of binding with a substrate and/or other bacteria. The filamentsmay promote formation of a more even biofilm Bacteria in the genusGordonia may be capable of degrading one or more organic compounds, suchas benzene, toluene, ethylbenzene, o-xylene, p-xylene, and/or m-xylene.In some embodiments, a biofilm including bacteria in the genus Gordoniamay be capable of degrading rubber compounds, desulphurize aromatics,and/or degrade pyridine compounds. Bacteria in the genus Gordonia may becapable of removing sulfur from petrochemical products. In anembodiment, bacteria in the genus Gordonia may produce biosurfactantsthat facilitate remediation and/or degradation of organic andmetal-based contamination. Biosurfactants may assist in thesolubilization of various pollutants and/or allow bacteria to morerapidly uptake pollutants for degradation or immobilization.

Bacteria in the genus Gordonia may go into a state of latency duringperiods of stress, introduction of a toxin, nutrient deprivation, and/oroxygen depravation. Bacteria in the genus Gordonia may be capable ofreviving out of the state of latency once the environment becomesconducive to the bacteria. It may be advantageous to utilize bacteriacapable of going into a latent state and reviving, so that bacteria in abiofilm may not die if the environment, such as in a bioreactor, changessignificantly.

Bacteria in the genus Gordonia may cause foaming in wastewater treatmentsystems. However, when bacteria in the genus Gordonia are coupled to asubstrate, foaming is inhibited and gene-up regulation occurs causingthe bacteria to be capable of reducing contaminants from water. Thephenomena of bacteria possessing a greater ability to degrade and/orreduce contaminants more efficiently when bound (e.g., gene-upregulation) is not limited to bacteria in the genus Gordonia but ispresent in several types of bacteria. Using bacteria with increasedcontamination reduction abilities when bound allows formation of a morestabile biofilm (e.g., since bacteria are coupled to the substrate)and/or a more efficient biofilm.

In some embodiments, the biofilm may include bacteria of the phylumProteobacteria phy. nov., class Alphaproteobacteria, orderCaulobacterales, family Caulobacteraceae, and/or genus Caulobacter.Bacteria in the genus Caulobacter may convert heavy metals such asmercury, copper, cadmium, and cobalt in aqueous solutions into chemicalforms that are less toxic, less soluble, and/or precipitate out ofsolution. Some bacteria in the genus Caulobacter have resistance to someantibiotics such as chloramphenicol, tetracycline, erythromycin, andtobomycin. Resistant bacteria may be from plasmid transfer betweenantibiotic resistant intestinal or human associated bacteria found inwastewater and bacteria in the genus Caulobacter.

Bacteria in the genus Caulobacter are oligotrophs and may be capable ofsurviving in low carbon concentration environments. In some embodiments,bacteria in the genus Caulobacter may be capable of forming a uniformbiofilm due to the bacteria shape. Bacteria in the genus Caulobacterhave a motile stage characterized by a swarmer cell and a sessile stagecharacterized by a stalk shaped cell. The stalks of the bacteria in thegenus Caulobacter may grow. It may be desirable to use a bacteria with agrowing stalk since the bacteria may be better able to survive changesin environment. For example, if nutrients proximate a bacterium'slocation are depleting, then the stalk of the bacterium in the genusCaulobacter may grow and the bacterium can be positioned in a newlocation with a more nutrients.

While some bacteria are capable of forming a biofilm through thesecretion of polysaccharides, bacteria in the genus Caulobacter may becapable of forming a biofilm using a stalk. In an embodiment, usingbacteria with stalks may allow the creation of a more uniform biofilmwhen compared with a biofilm formed without the use of bacteria withfilaments. For example, a biofilm may be formed of a first layerincluding bacteria in the genus Caulobacter and one or more other layerscoupled to the bacteria in the genus Caulobacter. The stalks may becapable of coupling to the substrate but may not be capable of couplingto other bacteria. In an embodiment, bacteria in the genus Caulobactermay only couple with a substrate at the holdfast at an end of its stalk.

In an embodiment, bacteria in the genus Caulobacter are capable offrequently entering and exiting a stationary phase. It may be desirableto utilize bacteria capable of entering and exiting the stationaryphase, because the bacteria may be more durable and/or capable ofsurviving environments with fluctuations in levels of nutrients.

In some embodiments, the biofilm may include bacteria of the phylumProteobacteria phy. nov., class Gammaproteobacteria, orderEnterobacteriales, family Enterobacteriaceae, and/or genus Enterobacter.Bacteria in the genus Enterobacter may be enteric, anerobic, and aheterotroph. Bacteria in the genus Enterobacter may produce hydrogenwhen metabolizing organic compounds. Bacteria in the genus Enterobactermay be capable of degrading aromatics, such as 2,4,6-trinitrotoluenethat is commonly found in wastewater produced in munitions production.Bacteria in the genus Enterobacter may be capable of degrading nitrateesters, such as pentaerythritol tetranitrate and glycerol trinitrate.

In some embodiments, the biofilm may include bacteria of the phylumFirmicutes phy. nov., class Bacilli, order Bacillales, familyBacillaceae, and/or genus Bacillus. Bacteria in the genus Bacillus maybe good oligotrophs and capable of surviving in an environment with alow concentration of organic compounds. Bacteria in the genus Bacillusmay be capable of degrading organic compounds, such as organic compoundsproduced from plant and animal sources (e.g., cellulose, starch, pectin,proteins, hydrocarbons). In an embodiment, a biofilm including bacteriain the genus Bacillus may cleave long chain biopolymers into monomersthat are degradable by other bacteria. Bacteria in the genus Bacillusmay be cable of nitrification, denitrification, and/or nitrogenfixation. Bacteria in the genus Bacillus may be capable of fermentingcarbohydrates, producing glycerol and butanediol, producing enzymes forutilization in detergents, paralyzing insects, degrading biopolymers,and/or synthesis for use in industrial processes such as the productionof antibiotics.

In some embodiments, it may be desirable to utilize bacteria in thegenus Bacillus to create a biofilm capable of surviving in harshenvironments. Bacteria in the genus Bacillus may produce spores that arehighly resistant to stressful environments and/or toxic environments.Bacteria in the genus Bacillus may synthesize antibiotics that killproximate bacteria and cause the dead bacteria to lyse and release theircontents. Bacteria in the genus Bacillus may absorb the nutrientsreleased by the ruptured cells. This process may require less energythan forming spores.

In some embodiments, the biofilm may include bacteria of the phylumProteobacteria phy. nov., class Gammaproteobacteria, orderPseudomonadales, family Pseudomonadaceae, and/or genus Pseudomonas.Bacteria in the genus Pseudomonas may be good heterotrophs. Bacteria inthe genus Pseudomonas may be capable of degrading organic compounds,such as trichloroethylene. In an embodiment, bacteria in the genusPseudomonas may degrade monomer organic compounds. Bacteria in the genusPseudomonas may be capable of degrading aromatic organic compounds suchas toluene, xylene, naphthalene, or polynuclear aromatic organiccompounds. In certain embodiments, bacteria in the genus Pseudomonas mayprefer to degrade simple organic compounds when compared to otherorganisms.

In some embodiments, it may be desirable to include bacteria in thegenus Pseudomonas in a biofilm since they are capable of withstandingfluctuations in environment. Bacteria in the genus Pseudomonas mayproduce o-acetylated alginate that encapsulates the bacteria to protectthe bacteria from stressful environments. Bacteria in the genusPseudomonas may have filaments. The filaments may help bacteria in thegenus Pseudomonas to attach to substrates and/or other organisms. Thefilaments and production of alginate by bacteria in the genusPseudomonas may promote formation of a biofilm and/or formation of abiofilm coupled to a substrate.

In certain embodiments, the biofilm may include bacteria of the phylumProteobacteria phy. nov., class Betaproteobacteria, order Rhodocyclales,family Rhodocyclaceae, and/or genus Zoogloea. Bacteria in the genusZoogloea may be a good heterotroph. Bacteria in the genus Zoogloea maybe capable of degrading high concentrations of proteins. Bacteria in thegenus Zoogloea may produce exopolysaccharide that contributes to theability of a biofilm containing bacteria in the genus Zoogloea totolerate fluctuating, stressful, and/or toxic environments.

In various embodiments, the biofilm may include bacteria of the phylumActinobacteria phy. nov., class Actinobacteria, order Actinomycetales,suborder Corynebacterineae, family Nocardiaceae, and/or genus Norcardia;bacteria of the phylum Proteobacteria phy. nov., class Gammaproteobacteria, order Thiotrichales, family Thiotrichaceae, and/or genusThiothrix; and/or bacteria of the phylum Proteobacteria phy. nov., classGamma proteobacteria, order Thiotrichales, family Thiotrichaceae, and/orgenus Beggiatoa. Bacteria of the suborder Corynebacterineae and bacteriaof the family Thiotrichaceae may have similar behavior. For example,both may experience gene-up regulation of metabolic activity whenattached to a substrate. In an embodiment bacteria of the suborderCorynebacterineae and bacteria of the family Thiotrichaceae may causefoaming in a container when planktonic.

In some embodiments, one or more bacteria generators may provide one ormore of the bacteria that form, supplement, and/or replenish the biofilmin a container. A bacteria generator may be a container capable ofincubating one or more types of bacteria. In one embodiment, bacteriagenerator may produce more than one type of bacteria simultaneously. Inother embodiments, a system may include a plurality of bacteriagenerators, one bacteria generator for each strain or set of strains ofbacteria that form the biofilm Bacteria generators may be BioAmp® typybacteria generators, commercially available from NCH Corp (Irving,Tex.). Bacteria generators may include one or more nutrient sourcesand/or be coupled to one or more containers such that bacteria from thebacteria generator is provided to the container. Bacteria generator maybe capable of producing a predetermined amount of bacteria in less than48 hours. In an embodiment, bacteria generator may be capable ofproducing a predetermined amount of bacteria in less than 24 hours. Inan embodiment, bacteria generator may facilitate rapid formation of abiofilm in a bioreactor, since bacteria can be supplied to the biofilmto supplement growth of the bacteria in the bioreactor. Bacteriagenerator may be capable of producing different combinations and/orratios of bacteria during use. In addition, unlike many automatedbacteria incubators, the bacteria generator may be capable ofinoculating the bacteria in the bacteria generator, as desired.

FIG. 8 depicts an embodiment of a bacteria generation system 800 thatincludes a plurality of bacteria generators 810 that generate bacteriato be used in a bioreactor. Each bacteria generator 810 may be operatedsimultaneously or individually to generate bacteria. In someembodiments, each bacteria generator 810 is used to generate a differentstrains of bacteria. Alternatively some or all of the bacteriagenerators may generate the same strain or strains of bacteria. Bacteriageneration system 800 includes fluid supply system 820 which includespump 822 and a plurality of valves 824. Pump 822 is coupled to a fluidsource and transfers fluids from the fluid source to one or more ofbacteria generators 810. The fluid source may be water or a water basedbacterial growth medium. If water is used as the fluid source, theprocess of generating bacteria includes adding bacterial growth mediumto the bacteria generators being used to generate the bacteria. One ormore of valves 824 may be opened to appropriately direct fluid from pump822 to one or more of the bacteria generators.

Each of bacteria generators 810 include a recirculation conduit 830 anda drain conduit 840. Recirculation conduit 830 is used to circulate thefluids out of, and back into, a bacteria generator. This creates thenecessary agitation/mixing to ensure proper growth of the bacteria inthe bacteria generator. By using a recirculating mixture, mechanicalagitation of the bacteria generators is not necessary. Drain conduits840 allow bacteria formed in bacteria generators 810 to be removed andcollected for use in a bioreactor. The generated bacteria are collectedin a bacteria collection tank 850. Bacteria collection tank 850 iscoupled to bacteria transfer pump 855, which sends bacteria, in someembodiments, to bacteria inlet conduit 740 of the sedimentation system(See FIG. 7).

Bacteria used in bacteria generators 810 may be in a preserved state. Inone embodiment, bacteria are generated using bacteria generators byfilling one or more of bacteria generators 810 with an appropriateamount of water. Growth medium (for example as a dry powder, or as aconcentrate) is added to one or more of bacteria generators 810 and thegrowth medium is mixed with the water by recirculating the mixture untilsubstantially homogenous. Bacteria stored in a preserved state are addedto one or more of the bacteria generators and the mixture is mixed for atime sufficient to increase the concentration of bacteria in thebacteria generators used. After the bacteria is generated, the producedbacteria is drained from the bacteria generators into bacteriacollection tank 850. From bacteria collection tank 850 the generatedbacteria may be transferred to one or more bioreactors through thesedimentation system.

To preserve bacteria. one or more types of bacteria are incubated andallowed to grow and/or reproduce in the presence of one or morenutrients. In an embodiment, bacteria may be incubated and reproduce inone or more bacteria generators. The flow of nutrients is thenterminated and the bacteria are allowed to enter a starvation phase. Inan embodiment, the starvation phase for the bacteria may be identifiedby determining when exponential growth of the bacteria has ended. Thechange in the number of bacteria may be monitored spectroscopically. Thebacteria in the starvation phase may then be preserved.

In some embodiments, the bacteria may be inoculated prior topreservation. Bacteria in the starvation phase produce stress proteinsthat protect the bacteria from shock. Therefore, when bacteria areinoculated, a greater percentage of bacteria in the starvation phasewould be able to survive the shock due to the increased production ofstress proteins. Stressing bacteria prior to preservation may allowhardier bacteria to survive the stress of inoculation while the weakerbacteria may die during inoculation. Therefore, it may be advantageousto stress bacteria prior to preserving the bacteria, since the shock mayonly allow hardier bacteria to be preserved.

It may be advantageous, in some embodiments, to preserve bacteria in thestarvation phase. The starvation phase occurs during the stationaryphase of bacteria. During the starvation or stationary phase, the rateof change of the number of bacteria is approximately constant since thenumber of bacteria generated is approximately the same number ofbacteria that die. Using bacteria in the starvation phase may also bedesirable, since when starved bacteria are introduced into anenvironment with nutrients, the bacteria are hungrier and morecompetitive for the available carbonaceous material.

In some embodiments, bacteria in the starvation phase may be preservedas bacteria-alginate beads, where the bacteria is immobilized in a bead.To produce bacteria-alginate beads, bacteria is mixed with an alginate,such as sodium alginate. In an embodiment, alginate is added to anaqueous solution including the bacteria in the starvation phase. Inanother embodiment, bacteria in the starvation phase may be added to anaqueous alginate solution. The sodium alginate or a viscous aqueoussolution containing alginate may be autoclaved at a temperature fromapproximately 115° C. to approximately 125° C. The bacteria-alginatemixture is stirred. The viscosity of the bacteria-alginate mixture mayincrease while stirring. The bacteria-alginate mixture is then added toan aqueous solution containing calcium ions.

In an embodiment, the bacteria-alginate mixture is added in drops to theaqueous solution containing calcium ions. Bacteria-alginate particlesare allowed to form in the calcium ion solution. The bacteria-alginateparticles may be firm and not as compressible as a gelatinous substance.The bacteria-alginate particles may be separated from the solutionand/or dried. The bacteria-alginate particles may be filtered from thesolution in an aseptic environment. The preserved bacteria-alginateparticles may be stored until needed and/or used in bacteria generatorsin a system for the reduction of contaminants in water. In anembodiment, when the bacteria-alginate particles are revived in asolution of nutrients, the bacteria may consume and/or degrade thealginate portions of the particle.

The size and shape of the bacteria-alginate particles may becontrollable. The amount of bacteria-alginate mixture added or droppedinto the calcium solution may control the size of the particles formed.The bacteria-alginate mixture may be sprayed onto the aqueous solutioncontaining calcium ions to produce small substantially spherical-shapedparticles. Particles that are substantially cubic, pyramidal, conical,or irregularly shaped may also be formed.

In other embodiments, bacteria in the starvation phase may be preservedon hydrophobic substrates. To produce immobilized bacteria in thestarvation phase on a hydrophobic substrate, bacteria may incubate in asolution containing one or more hydrophobic substrates until thebacteria are in the starvation phase. Alginate is mixed in an aqueoussolution and may be autoclaved at a temperature from approximately 115°C. to approximately 125° C. The hydrophobic substrate that includes thebacteria in the starvation phase may then be introduced into the cooledalginate solution. Alginate may at least partially saturate thehydrophobic substrate. The hydrophobic substrate then may be contactedwith an aqueous solution containing calcium ions. The hydrophobicsubstrate may be separated from the solution and/or vacuum filtered. Thehydrophobic substrate may be allowed to dry. In certain embodiments, thehydrophobic substrate containing preserved bacteria in the starvationphase may be stored until needed, used in bacteria generator in a systemfor reduction of contaminants in water, and/or added to a container toform a biofilm.

Although adding bacteria-alginate mixture to calcium ions is described,other metal ions solutions may be used successfully as well, includingbarium, copper, or zinc metal ion solutions. It may be desirable to usea calcium ion solution because calcium is available at a low cost fromsources such as limestone and/or calcium is not generally considered acontaminant, unlike copper or zinc.

Preserving bacteria in particles or immobilizing bacteria on hydrophobicsubstrates may allow the preserved bacteria to be more resilient toenvironmental stress and/or toxins and/or may reduce cell mortality uponrevival. Unlike when using preservation methods currently known in theart, such during lyophilization or the formation of compressed tablets,the bacteria are not dried to desiccation when bacteria are in particlesor immobilized on substrates. Although lyophilized bacteria andcompressed pellet bacteria have long shelf lives, it may take a longperiod for the bacteria to acclimate to surroundings and return to anexponential growth stage. Bacteria in particles and immobilized onsubstrates may become physiologically active within a shorter period oftime since the cells do not have to be hydrated since they were notdesiccated to the same extent during preservation.

In some embodiments, the preserved bacteria in particles and/orhydrophobic substrate may be added to bacteria generator to producebacteria for a container in a system for the reduction of contaminantsin wastewater. The preserved bacteria may be revived from the starvationphase and enter exponential growth phase when introduced into an aqueoussolution containing nutrients. The preserved bacteria may consume thealginate in the particle and/or hydrophobic substrate. After a period ofincubation, the bacteria may then be introduced into a container to formand/or replenish a biofilm. In an alternative embodiment, preservedbacteria in or on hydrophobic substrate may be added directly to acontainer to form a biofilm.

Wastewater treated in a treatment system that includes one or morebioreactors may be further purified by passing the treated wastewaterstream to a purification system 600. Purification system may include oneor more filtration systems that receive an effluent stream from one ormore of the bioreactors and produces a filtered water stream. Examplesof filtration systems that may be used include, but are not limited to agranulated activated carbon filter or a membrane-based filter. Anactivated carbon filter may remove organic compounds, metal ions, fineparticles and/or bacteria from fluid flowing through activated carbonfilter. Membrane based filtration include reverse osmosis, micro, andultrafiltration membranes.

Metal removing system 600 may also include electrocoagulation andelectroplating systems. An electrocoagulation system may be used toprecipitate metal ions for removal. In an embodiment, anelectrocoagulation system may charge ions in a fluid between two chargedmetal objects (e.g., metal plates or rods) disposed at a fixed distancefrom each other. When an electrical potential is applied to the metalobjects, charged ions may bind to oppositely charged ions and form aprecipitate. The formed precipitates may float to a top surface or sinkto a bottom surface of the metal removing system for removal from thefluid. In an embodiment the precipitates may be filtered out of thefluid. An electroplating system may also include two charged metalobjects disposed at a fixed distance from each other. When an electricalpotential is applied to the metal plates, metal ions between the chargedmetal objects may become plated onto one or both of the metal objects.In some embodiments, a metal removing system may be capable of bothprecipitation and plating of metal ions. Metal removing systems aredescribed in further detail in U.S. Pat. No. 7,914,662, which isincorporated herein by reference.

Purification system 600 and bacteria generation system 800 may bepositioned in a structure 900. In some embodiments, structure 900 is aportable structure. For example, structure 900 may be an a high cube,20′ ISO container. FIG. 9 depicts a structure 900 that includes apurification system 600, a bacteria generation system 800, a powergenerator 910, a controller system 920, electrical panels 922, a cooler930 for the preservation of bacteria, and a cooling system 940 forcontrolling the temperature inside the structure. Power generator 910 isused to generate power to operate controllers, valves and sensors duringoperation. Alternatively, the power may come from an available powergrid. Power generator also supplies power for bacteria generator, andcooling systems. In some embodiments, generator is a diesel or gaspowered generator. Controller 920 may be capable of controllingoperation of the components of the wastewater treatment system. Forexample, controller 920 may be a computer that is coupled, throughelectrical panels 922 to various valves and sensors in a wastewatertreatment system. Computer controller 920 is capable of implementingsoftware configured to allow automatic, semi-automatic, and/or manualoperation of the wastewater treatment system. Cooler 930 may be arefrigerator that is capable of maintaining bacteria in a dormant state.Cooling system 940 may b a fan or air conditioning unit that allows thetemperature inside the structure to be controlled.

In some embodiments, a wastewater treatment system may be divided intoseparate portable structures. A portable structure may be formed ofplastic, metal, and/or other materials. A portable structure may includeone or more coatings. A coating may inhibit corrosion and/or facilitateremoval of solids from the portable structure. For example, a portablestructure may have a polytetrafluoroethylene coating to inhibitcorrosion and to inhibit solids from adhering to the container. In someembodiments, a footprint of a portable structure may be substantiallysquare, substantially circular, substantially oval, substantiallyrectangular, and/or irregularly shaped.

For example, a non-buffered wastewater treatment system may include atreatment unit 1000 and a control unit 1010, as depicted in FIG. 10.Treatment unit 1000 may include one or more bioreactors and one or moresedimentation systems in a portable structure. An example of a treatmentunit is depicted in FIG. 6. Control unit 1010 includes a purificationsystem, a bacteria generation system, a power generator, controllers,and other equipment as described above. Non-buffered wastewatertreatment system may be positionable near a source of wastewater 1020and near a treated water retaining area 1030. Conduits 1015 are used tofluidically and electrically interconnect treatment unit 1000, controlunit 1010, wastewater source 1030, and treated water retaining area1030. Separating control unit from treatment unit helps to ensure thatwater sensitive components such as controllers and generators, areisolated from the water treatment areas.

A buffered wastewater treatment system may include a buffer unit 1105, atreatment unit 1100 and a control unit 1110, as depicted in FIG. 11.Treatment unit 1000 may include one or more bioreactors and one or moresedimentation systems in a portable structure. An example of a treatmentunit is depicted in FIG. 6. Control unit 1110 includes a purificationsystem, a bacteria generation system, a power generator, controllers,and other equipment as described above. Buffered wastewater treatmentsystem may be positionable near a treated water retaining area 1130.Conduits 1115 are used to fluidically and electrically interconnectbuffer unit 1105, treatment unit 1100, control unit 1110, and treatedwater retaining area 1130. System input conduit 1125 is used tointroduce wastewater into the system from various sources. For example,trucks carrying wastewater may be couplable to system input conduit 1125to allow the introduction of wastewater from various sources. Separatingcontrol unit from treatment unit helps to ensure that water sensitivecomponents such as controllers and generators, are isolated from thewater treatment areas.

EXAMPLES

The following examples are included to demonstrate preferred embodimentsof the invention. It should be appreciated by those of skill in the artthat the techniques disclosed in the examples which follow representtechniques discovered by the inventor to function well in the practiceof the invention, and thus can be considered to constitute preferredmodes for its practice. However, those of skill in the art should, inlight of the present disclosure, appreciate that many changes can bemade in the specific embodiments which are disclosed and still obtain alike or similar result without departing from the spirit and scope ofthe invention.

Example 1 Producing Bacteria in the Starvation Phase

Bacteria was incubated in a nutrient broth at a temperature of fromapproximately 25° C. to approximately 30° C. depending on which bacteriais being preserved. Bacteria in the genus Agrobacterium, Bacillus,Caulobacter, Enterobacter, Gordonia, Zoogloea and Peudomonas wereincubated at 30° C. Bacteria in the genus Agrobacterium and Zoogloeawere incubated at 26° C. The bacteria were allowed to incubate for 24 to72 hours without the addition of an additional amount of nutrients.Bacteria in the genus Agrobacterium, Bacillus, Enterobacter, andPeudomonas were incubated for 24 to 48 hours. Bacteria in the genusCaulobacter and Gordonia were incubated for 48 to 72 hours. Bacteriawere spectroscopically monitored to determine when exponential growthceases and bacteria have entered the starvation phase.

In one embodiment, a specific bacteria mixture for use in treatingwastewater includes Enterobacter cloacae, Pseudomonas putida,Pseudomonas stutzeri, Gordonia sp., Bacillus subtilis, Agrobacteriumsp., Caulobacter vibrioides, Caulobacter crescentus and bacteria in thegenus Zoogloea.

Example 2 Producing Bacteria-Alginate Particles

40 g of sodium alginate was mixed into an aqueous solution to formsolution more viscous than water. The alginate solution was autoclavedat 121° C. for 30 minutes. The alginate solution was then allowed tocool. 500 ml of bacteria in the starvation phase, prepared according toExample 1, was added to the alginate solution to form bacteria-alginatemixture. The bacteria-alginate solution was agitated. Thebacteria-alginate solution was added in drops into 2 L of 0.55 M calciumchloride solution. The calcium chloride solution was mixed continuously.Particles, with a length and a width of approximately 5 mm, formed inthe calcium chloride solution. The particles were then filtered under atleast a partial vacuum using Whatman 40 filter paper, commerciallyavailable from Whatman (Middlesex, United Kingdom). The particles werethen dried and stored.

In this patent, certain U.S. patents, U.S. patent applications, andother materials (e.g., articles) have been incorporated by reference.The text of such U.S. patents, U.S. patent applications, and othermaterials is, however, only incorporated by reference to the extent thatno conflict exists between such text and the other statements anddrawings set forth herein. In the event of such conflict, then any suchconflicting text in such incorporated by reference U.S. patents, U.S.patent applications, and other materials is specifically notincorporated by reference in this patent.

Further modifications and alternative embodiments of various aspects ofthe invention will be apparent to those skilled in the art in view ofthis description. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the invention. It is to beunderstood that the forms of the invention shown and described hereinare to be taken as examples of embodiments. Elements and materials maybe substituted for those illustrated and described herein, parts andprocesses may be reversed, and certain features of the invention may beutilized independently, all as would be apparent to one skilled in theart after having the benefit of this description of the invention.Changes may be made in the elements described herein without departingfrom the spirit and scope of the invention as described in the followingclaims.

The invention claimed is:
 1. A system for reducing contaminants in awastewater stream comprising: an inlet system, wherein the inlet systemreceives a wastewater stream comprising one or more contaminants; one ormore bioreactors, wherein one or more of the bioreactors comprise asubstrate, wherein bacteria in the wastewater stream at least partiallyadhere to the substrate; wherein the substrate comprises a plurality ofsheets, and wherein the sheets are oriented, with respect to each other,such that a plurality of passages are defined by the sheets; one or morefluid level sensors disposed in one or more of the bioreactors; acontroller coupled to one or more of the fluid sensors; and a pumpcoupled to the wastewater stream; wherein the controller controlsoperation of the pump to control the incoming flow of the wastewaterstream into the one or more bioreactors based on the fluid leveldetected by one or more of the fluid level sensors; wherein at least aportion of the contaminants in the wastewater stream are removed bybacteria in the one or more bioreactors during use.
 2. The system ofclaim 1, wherein the substrate comprises a polymer substrate.
 3. Thesystem of claim 1, wherein the substrate comprises a ceramic substrate.4. The system of claim 1, wherein one or more of the sheets of thesubstrate comprise ridges and/or grooves, and wherein the sheets arepositioned proximate to each other such that the ridges and/or groovesare at least partially aligned to define a plurality of passages.
 5. Thesystem of claim 1, wherein the substrate comprises a plurality ofcorrugated sheets, wherein the sheets are oriented, with respect to eachother, such that a plurality of passages are defined by the corrugatedsheets.
 6. The system of claim 1, wherein one or more of the bioreactorsare housed in a portable structure.
 7. The system of claim 1, whereinone or more of the bioreactors comprise an oxygen containing gas inletwherein during operation of the bioreactor oxygen containing gas passesthrough the oxygen containing gas inlet into the bioreactor.
 8. Thesystem of claim 6, further comprising a diffuser coupled to the oxygencontaining gas inlet, wherein during operation of the bioreactor oxygencontaining gas passes through the oxygen containing gas inlet into thediffuser and through the diffuser into the bioreactor.
 9. The system ofclaim 1, further comprising a filtration system coupled to one or morebioreactors, wherein the filtration system receives an effluent streamfrom one or more of the bioreactors and produces a filtered water streamfrom the effluent stream.
 10. The system of claim 1, further comprisinga grinding system coupled to the inlet system and the bioreactor inlet,wherein the wastewater stream is passed through the grinding system andtransferred to the bioreactor inlet during use, and wherein the grindingsystem reduces the size of solid matter in a water stream passingthrough the grinding system.
 11. A method of reducing contaminants in awastewater stream comprising: flowing a wastewater stream through one ormore of the bioreactors, wherein the one or more bioreactors comprise: asubstrate comprising a plurality of sheets, and wherein the sheets areoriented, with respect to each other, such that a plurality of passagesare defined by the sheets, wherein bacteria in the wastewater stream atleast partially adhere to the substrate; determining a fluid levelwithin one or more of the bioreactors; altering the incoming flow rateof the at least partially clarified wastewater stream into the one ormore bioreactors based, in part, on the fluid level detected by one ormore of the fluid level sensors; allowing the wastewater stream tointeract with bacteria in one or more of the bioreactors for asufficient amount of time to allow the bacteria to reduce theconcentration of contaminants in the wastewater stream.
 12. The methodof claim 11, wherein the substrate comprises a polymer substrate. 13.The method of claim 11, wherein the substrate comprises a ceramicsubstrate.
 14. The method of claim 11, wherein one or more of the sheetsof the substrate comprise ridges and/or grooves, and wherein the sheetsare positioned proximate to each other such that the ridges and/orgrooves are at least partially aligned to define a plurality ofpassages.
 15. The method of claim 11, wherein the substrate comprises aplurality of corrugated sheets, wherein the sheets are oriented, withrespect to each other, such that a plurality of passages are defined bythe corrugated sheets.
 16. The method of claim 11, wherein one or moreof the bioreactors are housed in a portable structure.
 17. The method ofclaim 11, wherein one or more of the bioreactors further comprise anoxygen containing gas inlet wherein the method further comprises passingoxygen containing gas through the oxygen containing gas inlet into thebioreactor.
 18. The method of claim 11, wherein one or more bioreactorsfurther comprise a diffuser coupled to the oxygen containing gas inlet,wherein the method further comprises passing oxygen containing gasthrough the oxygen containing gas inlet into the diffuser and throughthe diffuser into the bioreactor.
 19. The method of claim 11, whereinthe method further comprises filtering an effluent stream from one ormore of the bioreactors to produce a filtered water stream from theeffluent stream.